SILUROID FISHES OF INDIA, BURMA AND CEYLON.
By SUNDER LAL HORA, D.Se., F.R.S.E, F.N.I., A.ssistant Superinten dent, Zoological Survey of India, and NIRMAL CHANDRA LAW, M.Se.
(Plates I and II.)
IX. FISHES OF THE GENERA Gagata BLEEKER AND Nangra DAY. Recently while working out collections of freshwater fishes from Assam and Travancore, considerable difficulty was experienced in separating Indian species hitherto referred to the genera Gagata Bleeker, Batasio Blyth and Nangra Day. This led us to examine the entire material of these genera in the extensive collections of the Indian Museum with very interesting results. In this article we propose to deal with the fishes of the genus Gagata, of which N angra is regarded as a synonym, while the genus Batasio is treated in d~tai1 in the next article of this series. Gagata Bleeker. 1858. Gagata, Bleeker, Ichthyol, Archipel, Ind. Prodromu8, I, p. 204: (orthotype G. typU8 Blkr. = Pimelodu8 gagata Ham.). 1860. Gagata, Blyth, J ourn. A8. Soc. Bengal XXIX, p. 152. 1863. Gagata, Bleekor, Ned. Tijdschr. Dierk. I, p. 90. 1864. Callomystax, Giinther, Cat. Fish. Brit. MU8. V, p. 218. 1877. Gagata, Day, Fi8h, India, p. 492. 1877. Nangra, Day, ibid., p. 493. 1911. Gagata, Regan, Ann. Mag. Nat. Bi8t. (8) VIII, p. 564. 1911. Nangra, Regan, ibid. (8) VIII, p. 564. 1913. Gagata, Weber & de Beaufort, Fish. Indo-Austral. Archipel. II, p. 268. In 1858, Bleeker provisionally proposed the generic name Gagata and included a number of heter
Later workers, however, regarded Gagata Bleeker as a valid genus and considered Gunther's Oallomystax as its synonym. Gunther had assigned only one species to this genus, but Day included 4 species in it-G. cenia (Ham.) with G. gagata (Ham.) as a synonym, G. itchkeea (Sykes), G. batasio (Ham.) and G. tengana (Ham.). According to Day, the range of the genus extends from the " Rivers of Sind, India (except Madras) and Burma." One more species-G. schmidti-has since been described by VOlzl from Sumatra. Day established another genus Nangra to accommodate Pimelodus nangra Hamilton, P. viridescens Hamilton and a new species from the Sone River (Nangra punctata) and remarked :- " This genus differs from Gagata in its barbels not being placed in a transverse line behind the chin: and in its gill-membranes not being confluent with a broad isthmus but rather deeply notched. It is allied in some respects to Macrones, but has no teeth on the palate, whilst its air-vessel is enclosed in bone. " Our studies have shown that the characters distinguishing the two genera intergrade into each other and can at best be used for separating species in the same genus. In order to discuss the systematic position of the above-mentioned species, it is necessary to know, in the first instance, the precise limits of the genus Gagata Hamilton. Though quite a number of Hamilton's species are inadequately characterised, there is no difficulty in recogni sing P. gagata, as its detailed description and figure leave no doubt about its identity. Reference may here be made to a few of its most salient features as given by Hamilton. i. There are eight barbles; the two nasal and the four mandi bulary barbels are shorter than the head, while the maxil lary barbels are rather longer, and have a membrane extend ing half way along their hinder edge. ii. The anal fin is provided with 17 rays. 111. The fins are edged with black. IV. The bones of the head are roughened with variously intersecting ridges. v. The jaws are crowded with minute teeth, while the tongue and the palate are smooth. vi. Both apertures of each nostril are circular and are separated only by the nasal barbel. Bleeker (1863, p. 90) based his genus Gagata on the following charac ters :- "Cirri 8, nasales 2, Bupramaxillares 2, inframaxillares 4. Palatum eden tulum. Dentes maxillis pluriBeriati parvi. Scutum capitis gra,noBum, fonticulis lateralibus. Cirri supramaxillares basi membrana muniti. Spina dorsi edentula. B.5." Gunther gave a good definition of the genus under Oallomystax and included the following additional important diagnostic characters in it:- i. The two pairs of mandibulary barbels are inserted in a trans verse series immediately behind the margin of the lower lip. The maxillary barbels are osseous to some extent. n. The eyes are without free orbital margins.
1 Volz, W., Revue Sui88e de Zool. XII, p. 470 (1904). 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 11
iii. The gill-openings a~e of moderate width, the gill-membranes being conHuent with the skin of the isthmus. Day added to the generic definition the character of the air-bladder which he found to consist of "two rounded portions, each of which is enclosed in an osseous cup." Regan in his synopsis of the genera of the Sisoridae defined the main skeletal features of Gagata an a. Text-fig. I.-Alimentary canal, dentition and air-bladder of Gagata gagata (Hamil ton). a. Alimentary canal. X 2i; b. Dentition. X 8; c. Air-bladder. X 3l. In view of what is stated above, the genus Gagata may be defined as follows :- Gagata comprises a group of Sisorid fishes in' which the body is com pressed and the snub-nosed head, though globular, is somewhat elevated, only rarely depressed. The upper surface of the head is provided with sharp, longitudinal ridges; it is covered with thin, smooth skin, but some. of the bones on the dorsal surface are variously roughened. The median fontanel is very conspicuous. The mouth is small, transverse and ventral. The lips are thick, continuous and somewhat fimbriated; the post-labial g~ooves are restricted round the corners of the mouth. The jaws are provided with small, villifo~m teeth; the palate is edentu lous. There are eight barbels; the nasal barbels are small and thin and are prolongations of the broad flaps separating the two nostrils on each side; these Haps, when present, cover a part of the posterior nostrils on each side; the maxillary barbels are osseous proximally, and are provided with membraneous Haps along the inner surface; the two pairs of mandibular barbels are shorter and mayor may not be situated in a more or less transver~~ ~~ri~~ behind the posterior lip. B2 12 Records of the Indian Museum. [VOL. XLIII, The skin in the thoracic region is smooth. The nostrils are close to gether. The eyes are subcutaneous. The gill-openings are fairly wide; the gill-membranes may be confluent with the skin of the isthmus, or deeply notched. The rayed dorsal fin is provided with a strong spine. The adipose dorsal is short but prominent. The pectorals arc provided with strong spines which are denticulated internally. The pelvics are J!orizontal and 6-rayed; they are situated behind the dorsal. The anal fin is short. The caudal fin is deeply forked. The air-bladder is divided into two rounded portions which are partially enclosed in bone and come in direct contact with the skin above the pectorals. There are 5 to 7 branchiostegal rays. . Regan distinguished Gagata from the other genera of the Sisoridae by the following combination of characters :- "Praecaudal vertebrae normal, with the ribs attached to the simple para pophysis and the neural arches without the latera.} processes·; end of transverse process of fifth vertebra appearing a.s a rugose plate behind the lateral cutaneous area. " Head somewhat compressed and elevated; tail and caudal vertebrae norma1. " Mesopterygoid smaller than metapterygoid, pelvis behind the dorsal. " Gill-membranes attached to isthmus." Further, he distinguished Nangra from Gagata by the fact that in thel former the gill-membranes are free from the isthmus. Having defined the generic limits of Gagata and Na'l1gra we may now consider the systematic position of the various species assigned to these genera. Hamilton's Pimelodus cenia is undoubtedly congeneric with his P. gagata. In the former the author seems to have overlooked the minute nasal barbels. GUnther appears to have overlooked this species entirely, for there is no mention of it in his Catalogue. Though in 1869, Day! recognised it as a distinct species, in his Fishes of India and the Fauna he considered it as a young form of Gagata gagata. We have examined a large series of specimens of both the species in the collection of the Indian Museum and are definitely of the opinion that they are quite distinct and represent two valid species of the genus Gagata. Day (loc. cit., 1877, p. 493) included Hamilton's Pimelodus batasi02 in the genus Gagata, and as he had no specimen for study he seems to have been greatly influenced by Hamilton's statement to the effect that "There is no slit under the throat. . " euvier and Valen ciennes3 included this species under Bagrus, Blyth4 under Batasio and GUnther6 under Macrones. We have examined several specimens of the species from the type-locality and find that Hamilton's statelnent with regard to a slit under the throat is not correct. In Hamilton's original drawing6 of the species the two nostrils of each side are sho\vn as situated wide apart, which precludes its being a· member of the Sisoridae. This species has been rightly assigned by Shaw and Sheb- 1 Day, F., Proc. Zool. Soc. London, p. 309 (1869). 2 Hamilton, F., llish. Ganges, p. 179 (Edinburgh: 1822). 3 euvier, G. and Valenciennes, A., Hist. Nat. Poisson XIV, p. 425 (1839). «Blyth, E., Journ., As. Soc. Bengal XXIX, p. 150 (1860). o Gunther, A., Cat. Fish. Brit. Mus. V, p. 83 (1864). 6 Day, F., Fish. India, pI. xcix, fig. 5 (1877); Hora, S. L., Mem. Ind . .A1U3. IX, pI. xxii, fig. 3 (1929). 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 13 beare1 to the genus Batasio Blyth, which is dealt with in the next article of this series. As regards the true systematic position of Pimelodus tengana Hamil ton there is some difficulty. It has been included under the genus Bagrus by Ouvier and Valenciennes, Batasio by Blyth, Macrones by Gunther and Gagata by Day. This species was collected by Hamilton in the Brahmaputra and in his original notes the description is dated "Gualpara, 29th July, 1808." To elucidate its systematic position attention may be directed to the following salient features as noted by Hamilton. :- 1. There are eight barbels shorter than the head. 2. The anal fin possesses fourteen rays. 3. It is a small fish of about 3 inches in length. 4. The back is marked with many black dots, which are collected into a spot above each pectoral fin, and also on the crown of the head. The fins of the back and tail are also dotted, so that the edge of the last is black, and several spots are formed on the first. 5. Both openings of each nostril are circular, with a tendril between them. 6. Under the lower jaw there is no slit. Though it is stated by Hamilton that the two openings of each nostril have a barbel between them, his figure shows that these openings are situated widely apart and that the posterior one is provided with a barbel at the anterior end. It would thus appear that the species can not be referred to the Sisoridae, but belongs to the Bagridae. It seems to belong to the genus Batasio and is conspecific with Blyth's B. affinis. vVe shall elucidate further the systematic position of this species in our account of the fishes of the genus Batasio. Hamilton's P. nang1'a, the type of Day's genus Nang'ra, differs from Gagata gagata and G. cenia in having longer barbels and deeply notched gill-membranes, though Hamilton in the description of this species also states "There is no slit under the throat." The bases of the mandi bular barbels are not situated in a straight line. As indicated above, we do not regard these differences of generic value, especially as Gagata itchkeea (Sykes) is a form intermediate in characters between Gagata and Nangra. In Pimelodus vi1'idescens, Hamilton mentioned only six barbels; evidently he overlooked the minute nasal barbels. The most signi ficant feature of this species is its greatly depressed head and anterior part of body. It is stated to possess a slit under the throat. From a careful study of Day's descriptions of Nangra punctata and Nangra 'l'iridescens and also from an examination of his drawings of the two species it seems probable that the two are identical, the latter being the juvenile form of the former. Two fresh specimens in our collection also confirm this view. In the nature of its gill-openings, G. viridescens agrees with G. nangra. Day recorded this species from Poona and one of us2 also recorded it fronl the Deccan. Re-examination of th@ 1 Shaw, G. E. and Shebbeare, E. 0., J ourn. Roy. As. Soc. Bengal, Scit:nce III, p. 97, fig. 98 (1938). 2 Hora, S. L., Rec. Ind. MU8. XXXIX, p. 19 (1937). 14 Records of the Indian Museum. [VOL. XLIII, material has shown that the Deccan specimens are referrable to G. itchkeea in which the isthmus is very narrow and the mandibular barbels are not situated in an absolute straight line. The only extra-Indian species of Gagata is G. schmidti V olz from Sumatra. Its salient features are the depressed head, It times broader than high; the small eyes, longitudinal diameter being contained 13 times in length of head; the absence of fontanels; the dorsal spine being dentated along the front and hind borders; the very narrow isthmus, and its almost uniform gray brown colour. The Indian species of the genus Gagata may be distinguished by the following key :- Key to the Indian species of the genus Gagata Bleeker. I. Nasal barbels small or rudimentary, being almost as long as or considerably shorter than longi tudinal diameter of eye. A. Dorsal fin considerably longer than head; both dorsals, anal, pectoral and pelvic fins black distally. [Gill-membranes united with a fairly broad isthmus; maxillary barbels slightly and mandibular barbels con siderably shorter than head; bases of mandibular barbels close together and in a transverse row; median groove on head extending to end of occipital process] G. gagata. B. Dorsal fin considerably shorter than head; distal portions of fins not coloured black. 1. Maxillary barbels longer than head. [Gill-membranes united with a very narrow isthmus; mandi bular barbels somewhat shorter than head; bases of inner mandi bular barbelS somewhat in ad vance of those of the outer; median groove on head extend ing as.,far as posterior border of orbit ~nd followed by a small, median, oval fontanel] G. itchkeea. 2. Maxillary barbels considerably shorter than head. a. Bases of mandibular barbels close together and in a transverse row. [Gill membranes united with a narrow isthmus; width of head considerably less than its length in front of pec torals; median groove on head extending to base of occipital process] G. cenia. b. Bases of mandibular barbels set widely apart, and at different levels. [Gill membranes united with each other and the isth mus; head almost as broad as its length in front of pectorals; median groove on head extending to base of occipital process] G. viridescens. II. Nasal barbels almost as long or longer than head. [Bases of mandibular barbels set widely apart, and at different levels; gill-membranes united with each other across the isthmus; maxillary and outer mandibular barbels much longer than head; median groove on head extending to base of occipital process] .• G. nangra. Gagata gagata (Hamilton). Plate I, figs. 1, 2. 1822. Pimelodus gagata, Hamilton, Fish. Ganges, pp. 197, 379, pI. xxxix, fig. 65. 1854. Pimelodus gagata, Bleeker, Verh. Bat. Gen. XXV, p. 58. 1858. Gagata gagata, Bleeker, Ichthyol. Archipel. Indici, Prodromus, I, Siluri. p.206. 1860. Gagata gagata, Blyth, J ourn. As. Soc. Bengal XXIX, p. 151. 1862. Gagata typus, Bleeker, Atl.Ichthyol. II, p. 7. 1864. Oallomystax gagata, Giinther, Oat. Fish. Brit. Mus. V, p. 218. 1869. Gagata typus, Day, Proc. Zool. Soc. London, p. 309. 1877. Gagata cenia, Day (in part), Fish. India, p. 492, pI. cxv, fig. 4. 1877. Oallomystax gagata, Beavan, Freshw. Fish. India, p. 149. 1889. Gagata cenia, Day (in part), Faun.,prit. Ind. Fish. I, p. 208, fig. 75. D. 1/6; A. 3-4/10-12; P. 1/9; V 1/5; C. 19. :. j' Gagata gagata is a medium-sized, stoutly-built species in which' the dorsal profile rises moderately to the commencement of the dorsal fin beyond which it slopes down gradually to the base of the caudal fin. The ventral profile is almost horizontal as far as the commencement of the pelvic fins and thereafter it rises gradually to the base of the caudal fin. The fish is compressed from side to side, more so in the posterior half; the dorsal surface forms a narrow ridge. The ventral surface in front of the pelvic fin is somewhat flattened. The head is broadly pointed in front; its length is ~ontained from 3·61 to 3·93 times in' the standard length. The height of the head at the occiput is contained from 1·05 to 1·45 times and its width from 1·25 to 1·57 times in its length. The snout is prominent and' globular; it is produced in front of the mouth for a short distance. The eyes are dorso-Iateral in position and are situated nearer to the posterior margin of the operculum than to the tip of the snout. The diameter of the eye is contained from 2·65 to 3·76 times in the length of the head, from 0·89 to 1·58 times in the length of the snout and from 0·65 to 1·20 times in the inter-orbital width. The two nostrils of each side are fairly pro minent, close together and situated 'much nearer to the tip of the snout than to the eye. The dorsal surface of the head is covered with smooth skin but is marked with bony ridges. The median groove on the head commences from in front of the nostrils and is continued with slight' variatiens to the end of the occipital process which misses the basal bone of the dorsal fin by a short distance. The occipital process is long and narrow, almost 4 to 5 times as long as broad at its base. The mouth is small and horizontal; it is bordered by thick and slightly fimbriated lips which are continuous at the angles of the mouth. There are patches of small, villiform teeth in the jaws. There are four pairs of barbels; the nasal barbels are small and thin and are rarely as long as the longitudinal diameter of eye. The maxillary barbels possess 16 Records ojl the Indian Museum. [VOL. XLIII, stiff bony bases and membranous flaps along the inner side of the proxi malone-third of their lengths. These barbels rarely exceed the length of the head. The two pairs of mandibular barbels have somewhat swollen bases which are arranged in a transverse row behind the lower lip; these barbels are shorter than half the length of the maxillary oarbels. The gill-opening is restricted on the ventral surface; the distance between the two openings is contained from 0·55 to 0·92 times in the diameter of the eye. The depth of the body is contained from 3·34 to 4·37 times in the standard length. The caudal peduncle is well formed; its least height is contained from 1-28 to 2-00 times in its length. Two oval patches vf skin above the pectorals indicate the areas where the air-bladder comes directly in contact with the skin. The cubito-humeral processes are fairly well marked. The anal opening is situated nearer to the commencement of the caudal fin than to that of the pectorals. The urino-genital openingsl are separate; in the female they are situated immediately behind the anus and form a slit-like aperture bordered by fleshy lips which project in the form of a short papilla-like structure distally. In the male the urinary opening is situated on a papilla behind the anus. The dorsal fin is pointed and situated almost wholly in advance of the pelvic fins; it is longer than the head; its spine is long, pointed and almost as long as, slightly shorter or longer than the head. It is finely serrated along the distal one-third of the anterior border. The adipose fin is short, but well marked; its base is somewhat longer than that of the rayed dorsal. The pectoral fins are also pointed and are placed only slightly above the ventral surface; they do not extend to the base of the pelvic fins. The pectoral spine is strong and denticu lated internally; its outer border is provided with a few teeth at the distal end_ The pelvic fins extend considerably beyond the anal open ing and their outer rays are pointed. The anal fin is of moderate length and the caudal fin is deeply forked with both the lobes pointed, the upper lobe is somewhat better developed than the lower. The general colour of the body is opaque yellow verging to dull gray. The greater part of the pectorals, the distal halves of the dorsal, pelvic, and anal fins are conspicuously coloured black. The caudal fin is whitish. The colouration of the species is one of its most characteristic features. Distribution.-Unfortunately a number of specimens of Gagata gagata in the collection of the Indian Museum do not bear locality labels, but it seems probable that the species is found in the Ganges, Brahmaputra and Irrawadi River systems. It is represented in the collection from Allahabad, Calcutta, Khulna and Prome. It is said to attain a foot in length. 1 Urino-genital structures similar to those described here are erroneously termed by. Moo~erjee, Mazumdar and Das Gupta as " vagina" and H penis" (Ind. Jount. Vet. Sc". A'1wmql Husb. X, p. 295, 1940). The authors seem to have ignored the fact that in teleosts the" urinary opening may be separate or confluent with that of the genital duc~s and is frequently placed on a more or less prominent papilla (papilla urogenitalis). If sepa~ate! the urinary opening is behind the genital; and if a papilla is developed, its extremIty IS perforated by the urethra, the genital opening being situated near the base" (Gunther, Introduction to the Study of Fishes, p. 156, 1880)...... Measurements in millimetres of the specimens of Gagata gagata (Ham.) ~ .....~ Puear R., Prome, ~ Allahabad. Hooghli R., Bengal. Khulna, Burma. Locality unknown. Bengal. rn ~ A A r- 1 ,- Standard length 102·0 77·0 79·0 94·0 97·5 83·5 118·0 81·5 90·0 90·5 92·0 120·0 139·0 143'0 0 Length of head 26-0 20-0 20-5 24·5 26·0 22·0 30·5 21'5 23'5 23·0 23·5 32·0 38·5 a~'o =~ Height of head at occiput 20·5 16·0 19·5 21·0 20·5 17-0 21-0 16-5 19·0 19·5 17-0 26·0 27·5 28'5 ~ ~ Width of head 18·5 15·5 13·0 19'5 18·5 17·5 19·5 17·0 16·5 17'5 16·0 23·0 25·0 25-0 ;Z Length of snout 10·0 8·0 8·5 9·5 10·5 8·5 12·5 8·5 10·0 10·0 9·5 13·5 13·0 16'0 Diameter of eye .• 8·5 6·5 5·0 8·0 8·0 7·0 10·5 7·5 7·0 7·5 6·5 8·5 14'5 12-0 9 t-t Interorbital width 8·0 7·0 6·0 7'5 9·0 8·0 8·0 6-5 8-0 7·0 7·0 9'5 9'5 9'5 ~ Depth of body .. 28·5 23-0 21·0 26·0- 26·5 22-5 27-0 21'5 26-5 25·5 24·5 33-0 36-0 33'5 ~ Length of caudal peduncle 17·0 9-0 11-0 14·0 13-0 13·0 18'5 10-5 12·0 13·0 13·5 16·0 21'5 23'0 ~. ~ "'i c 8,5 ~. Least height of caudal ped- S-5 7-0 7'5 7·5 7·5 11·0 7·0 8·0 8·0 8·5 11·0 13·0 11.5 ~ uncle. ~ Longest ray of dorsal 33·5 25·0 23·5 31·5 37·5 27·5 29·0 28-0 30·0 35·0 34·5 40·5 42·0 38'5 ~. ~ Length of dorsal spine 27·5 20-0 19·0 27·0 29·0 23·0 25·0 23-5 24·0 29·0 25·0 33·5 35'5 D. ~ ~ ~ Length of pectoral 28·5 22-0 21-5 28·0 29-5 22·0 30·5 22-0 14-0 27·0 28-0 32·5 43-5 42'0 ~ Length of pectoral spine 25-5 24·5 21-5 21·0 22-0 25-0 24-5 30-5 19·0 19·0 26·5 28·0 39·0 37'0 ~ Length of ventral 18-0 13-0 13·5 18·0 18-5 15·5 18·0 14·0 14·5 17·5 15·5 21-0 26'5 25'5 ~ ~. ~ Longest ray of anal 21-0 D. 12-0 18'5 19-0 D. 18-5 15-0 17·0 21·0 17·0 D. 30·0 D. Length of base of anal 16-0 11·0 11·0 13·5 13·5 11·5 17·0 12·0 14·0 15·0 14·5 17·5 19-5 20·0 Length of base of adipose 16·5 11·5 10-5 14'5 13·0 8-5 15·0 12-5 10·5 10·0 14·0 14·0 16·5 16·0 ~ dorsal. . -:J 18 Records of t~e Indian M'Useum. [VOL. XLlIl, Gagata itchkeea (Sykes). Plare I, figs. 3, 4. 1840. Phractocephalus itchkeea, Sykes, Tran8. Zool. Soc. London II, p. 373, pl.lxvii,fig.l. 1849. Pimelodu8 itchkeea, Jerdon, Madra8 Journ. Litt. Sci. XV, p. 341. 1854. Bagrus itchkeea, Bleeker, Verk. Bat. Gen. XXV, p. 56. 1864. Macrone8 itchkeea, Oat. Fisk. Brit. MU8. V, p. 84. 1876. Hemipimelodu8 itchkeea, Day, Journ. Linn. Soc. London, Zoology XII, p.571. 1877. Gagata itchkeea, Day, Fish. India, p. 492, pI. cxv, fig. 6. 1889. Gagata itchkeea, Day, Faun. Brit. Ind., Fish I, p. 209. 1937. 'Nangra virideseens, Hora (nee Hamilton), Bee. Ind. Mus. XXXIX, p. 19. 1937. Nangra viridescens, Hora & Misra (nee Hamilton), Journ. Bombay Nat. Hist. Soc. XXXIX, p. 511; ibid. XL, p. 23, 1938. D. 2/6; A. 2-3/9-10; P. 1/8; V 1/5; C. 18-19. Gagata itchkeea is a small, almost cylinderical fish in which both the dorsal and the ventral profiles are slightly arched. The body is only slightly compressed anteriorly, but in the region behind the pelvic fins the compression is' more marked. The ventral surface in front of the pelvic fins is only slightly flattened and, in consequence, the pec toral fins are placed at a considerably higher level than the ventral surface. The head is short, globular and rounded anteriorly; its length is contained from 3·57 to 4·05 times in the standard length. The height of the head at the occiput is contained from 1·25 to 1·50 times and its width from 1·16 to 1·50 times in its length. The snout is so much rounded that one gets the impression of a pug-headed fish and the nos trils are almost directed anteriorly; it projects beyond the mouth for a short distance. The eyes are large and dorso-Iateral in position; they are not visible from the ventral surface. The diameter of the eye is cOhtained from 2·20 to 2·75 times in the length of the head, from 0·60 to 1·00 times in the length of the snout and from 0·63 to 0·87 times in the interorbital distance. The nostrils are large and well formed and are situated almost midway' between the tip of the snout and the eyes. The median groove on the head extends from between the nos trils to the base of the occipital process, but anteriorly there are lodged in it one large and one small fontanels. Mter the second fontanel the groove is very shallow and hardly perceptible posteriorly. The edges of the groove are slightly raised to form longitudinal ridges. The occipital process is long and narrow, its length is about 3 times its width at the base; it is separated from the basal bone of the dorsal fin by a short distance. The mouth is small, inferior and horizontal; it is bordered by fleshy lips whic~ are continuous and free at the angles of the mouth. The teeth are small, villiform, and hardly perceptible. There are four pairs of barbels; the nasal barbels are small and con siderably shorter than the diameter of the eye; the maxillary barbels are longer than the head and their basal parts stiff; the membrane in 1941.] S. L. HORA & N. C. LAW: Silu·roid Fishes of India. 19 their axils is little developed; the two pairs of mandibular barbels are almost equal and are as long as the head behind the anterior border of the orbit. The bases of the mandibular barbels are not situated exactly in a transverse line behind the lower lip, but those of the inner pair are slightly in advance of those of the outer. The gill-membranes are attached to the isthmus but the gill-openings are separated by a distance which is generally less than one-fifth of the diameter of the eye. The depth of the body is contained from 4·00 to 5·41 times in the standard length. The least height of the caudal peduncle is contained from 1·14 to 1·85 times in its length. The portion of the body where the air-bladder comes in close contact with the skin is not well marked externally, but the cubito-humeral processes are fairly distinct. The anus is followed by a small urino-genital papilla. The dorsal fin is situated in advance of the pelvic fins; it is generally shorter than the head. The dorsal spine is a strong prickle which is smooth along both the borders. The adipose dorsal is small, but well developed. The pectoral fin is pointed and almost reaches the base of the pelvic fins; its spine is strong and crenulated along the outer border but serrated for two-thirds of its length internally. The pelvic fins extend beyond the anal opening, but are separated from the anal fin by a short distance. The anal fin is short like the dorsal. The caudal fin is deeply forked; both the lobes are pointed, the upper being somewhat longer. Sykes noted that the colour of the fish is "yellowish glossy silver, inclining to greenish on the back, and silvery on the belly; marked with dark bluish brown broad spots along the back, head, and at the base of the rays of the tail" Day remarked that the colour is "yellowish-bronze, becoming silvery on the sides and abdomen: some dark blotches along the back descending to half way down the sides. A black blotch on either lobe of the caudal, and another on the dorsal fin" In the specimens examined by us the colour varies only slightly from the earlier descriptions, and the saddle-shaped black bands on the body though only faintly marked in some are fairly conspicuous in others. Distribution.-As stated by Day, G. itchkeea is found only in the rivers of the Deccan. In the collection of the Indian Museum, this species is represented from Deolali, Poona, Satara (Bombay Presidency) and from the Cauvery in the Coorg State. Remarks.-G. itchkeea is in~ermediate between G. gagata and G. nangra in several respects and on account of its wide gill-openings and the disposition of the bases of the mandibular barbels is liable to be referred to the genus N angra. I ts relatively longer barbels also show its affinity to G. nangra. Sykes considered it a close ally of Hamiltqn's Pimelodus tengana, which we have referred to the genus Batasio Blyth. G. itchkeea rarely exceeds three inches in length and seems to be very common in the waterways at Poona. Measurements in millimetres of the specimens of Gagata itchkeea (Sykes). Deolali. Poona. Satara. Coorg. Bombav Meema. market: ----A...... --___~ ,..-- ,----J'-~ Standard length 38·0 38'5 40-5 42-5 46·0 46-5 47·0 49·0 50·0 41·0 40·0 Length of head 10·0 10'5 10·0 11·0 12·5 11·5 13·0 13-0 14·0 11·0 10·5 ~ Height of head at occiput 7·0 7·0 8·0 7·5 8·5 9·0 9·0 9'5 10'5 7·5 7-5 ~ ~ ~ ~ Width of head 7·0 7·0 8·0 8·0 8·5 9-5 9·0 10·5 12·0 9·0 7·5 Length of snout 3·5 3'5 3·0 4·0 4·0 3·0 4·5 5",0 4·0 4·0 3-5 ~ ~ Diameter of eye 4·5 4'5 4·5 4·0 5·5 5·0 5·0 5·0 6·0 5-0 4·5 ~ ~ ""-f Interorbital width 3·0 3·0 3·0 3·5 3·5 3·5 3·5 4·0 4·0 3·5 3·0 ~ ~. Depth of body 8·0 9·5 9-Q 10·0 8-5 11·0 11·5 11·0 12·1> 9·0 8·0 ~ Length of caudal peduncle 4·0 5-5 6·5 7·0 5-0 7·0 7·0 7·5 8·5 5·0 4·0 ~ ~ ~ Least height of caudal peduncle 3·0 3-5 3·5 4·0 4·0 4·0 4·5 5·0 5·0 4·0 3·5 ~ Longest ray of dorsal __ 8·5 9-0 9·0 11·0 11·0 10·5 11·8 12·0 13·0 10·5 10·5 ~ Length of dqrsal spine 6·0 7-5 8·0 9·0 9·0 8·5 9·8 10·4 9·5 8·0 8·0 ~ Length of pectoral .. 11·0 11·0 10·5 12·0 12·0 12·5 14·0 13·5 15-5 13·0 13·0 Length of pectoral spine 9·0 g·O 9·5 10·0 10·5 11·5 12·5 12·0 14·0 11·0 11-5 r--t Length of ventral 7·0 6·0 6·5 8-0 7·5 7·0 8·0 8·5 9·5 7·5 6·5 -<0 ~ Longest ray of anal . - 8·0 7'5 8-0 7·0 8·5 9·0 lO'O 10·5 11-5 8·0 D. Length of base of anal .. 6·5 5'5 6'5 6-8 5·5 6·0 7·0 8·5 8-0 6·5 6·0 ~ t-t...... Length of base of adipose dorsal 8·0 5·0 5·5 6·5 5·0 6·0 7·0 7·0 7·5 5·5 6·0 t-f VVidth ofisthrnus 0·5 0'9 1·0 0·8 1·0 0·95 1·0 1-0 0-3 0-9 1-5 v..... 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 21 Gagata ceDia (Hamilton). Plate I, figs. 5, 6. 1822. Pimelodu8 eenia, IIamilton, Fisk. Ganges, pp. 174, 376, -pI. xxxi, fig. 57. 1854. Pimelodu8 eenia, Blecker, Verk. Bat. Gen. XXV, p. 58. 1869. Hemipimclodu8 eenia, Day, Proe. Zool. Soc. London, p. 308. 1871. Hemipimelodus eenia, Day, Proe. Zool. Soc. London, p. 288. 1877. Gagata eenia, Day (in part), Fisk. India, p. 492, pI. cxv, fig. 5. 1889. Gagata eenia, Day (in part), Faun. Brit. Ind. Fish. I, p. 208. 1890. Gagata eenia, Vinciguerra, Ann. Mus. Giv. Store Nat. Geneva (2) IX, p. 121. 1921. Gagata eenia, Hora, Bee. Ind. MU8. XXII, p. 182. 1938. Gagata eenia, Hora, Bee. Ind. MU8. XL, p. 180, fig. 6. 1939. Gagata eenia, Das, Bee. Ind. MU8. XLI, p. 448. D. 2/6; A. 2-3/10-12; P. 1/7-9; V 1/5; C. 17-19. Gagata cenia is a comparatively small and slender fish, in which the dorsal and the ventral profiles are slightly arched. The body, however, becomes considerably narrow in the caudal region. The ventral sur face in front of the pelvic fins is flattened and horizontal. The dorsal surface is somewhat rounded and the head and the body, except in the tail region, are moderately compressed. The head is flattened on the ventral surface and more or less rounded anteriorly; its length is contained from 3·62 to 4·47 times in the standard length. The height of the head at the occiput is contained from 1·29 to 1·87 times, and its width from 1·40 to 2·00 times in its length. The snout is prominent, globular and projects beyond the mouth for a con siderable distance. The eyes are large and dorso-Iateral in position; they are not visible from the ventral surface. They are situated either in the middle of the head or slightly nearer to the posterior margin of the operculum than to. the tip of the snout. The diameter of the eye is contained from 1·87 to 3·41 times in the length of the head, from 0·62 to 1·33 times in the length of the snout and froln 0·50 to· 0·85 times in the interorbital width. The nostrils are situated almost midway between the eye and the tip of the snout or slightly nearer to the former than to the latt.er. The head is covered with smooth skin, hut its dorsal surface is marked with two longitudinal bony ridges and the supra orbital bones are also slightly raised above the surface. The median groove on the head commences from in front of the nostrils and after a slight interruption is continued to a point in front of the base of the occipital process. The occipital process is. about three times as long as broad at its base and misses the basal bone of the dorsal fin by a short distance. The mouth is small, horizontal and crescentic; it is bordered by fleshy lips which are free and continuous at the angles of the mouth. The median portion of the upper lip is swollen and plica ted ; it forms a prominent fold in front of the mouth. There are small and villiform teeth in the jaws. There are four pairs of barbels; the nasal barbels are so minute that they are likely to be overlooked; the basal portions of the maxillary barbels are stiff and there is a tllick membrane in their axils; they are slightly shorter than the head; the mandibular barbels are considerably shorter and their bases are situated in a transverse series behind the lower lip. In a very large number of 22 Records of tke Indian Museum. [ VOL. XLIII, specimens there are two finger-like processes situated in the mid-ventral line between the bases of the inner mandibular barbels. Sometimes these structures are represented by nodules attached to the posterior lips, while i~ certain specimens they are entirely absent. These struc tures, like the barbels, are probably tactile in function. The gill-open ings are somewhat restricted on the ventral surface by a narrow isthmus; the distance between the gill-openings is contained from 0·15 to 0·63 times in the diameter of the eye. The depth of the bod y is contained from 4·0 to 6·0 times in the standard length. The least height of the caudal peduncle is contained from 1·27 to 2·14 times in its length. The portion of the body where the air-bladder comes in contact with the skin is not well marked exter nally and the cubito-humeral processes are not so prominent. The urino-genital openings are similar to those described above for Gagata gagata (vide supra, p. 16). The dorsal fin is obliquely truncate and its base is situated wholly in adva.nce of the pelvic fins; it is usually shorter than the head, but in rare cases it may be just as long as the head. The dorsal spine is a short, strong prickle which is smooth along the posterior border but is finely serrated along the anterior border, especially along the distal portion. The adipose dorsal is short but well marked. Generally the pectoral fin is shorter than the head, but sometimes it is equal to or even slightly longer than the head; they are separated from the pelvic fins by a considerable distance. The pectoral spine is denticulated in the middle along its inner border and serrated along the distal half of the outer border. The pelvic fins reach as far as or extend slightly beyond the anal opening. The anal fin is short and low. The caudal fin is deeply forked and both the lobes are sharply pointed; the upper lobe is somewhat longer than the lower. Hamilton noted that" The general colou'l' is silver, with some dusky on the back, and the bars descending to the lateral lines. The end of the tail is black; and the first fin of the back, and that of the tail, are stained with the. same colour. The eyes are silver-coloured." He had also noted that the back was marked with four transverse bars. Day, who regarded this species as comprising of young individuals only, stated that "The young are of a yellowish bronze colour, becoming silvery on the abdomen: they have three dark bands over the head and four more over the back, descending as low as the lateral-line. Caudal with a semi-lunar black band, or a black blotch on each lobe: a dark mark across the dorsal fin." The specimens in the collection of the In~ian Museum vary slightly as regards colouration but in general agree closely with Day's description. Distribution.-Hamilton described this species from the northern parts of Bengal, but as Day had confused Gagata gagata with G. cenia, it is not possible to accept the range of distribution of this species given by him. In the collection of the Indian Museum, it is represented from the' Punjab, Delhi, Nepal, Bihar, Orissa, Bengal, and Assam (including Chindwin Drainage System). It rarely exceeds six inches in length and was originally described by Hamilton from specimens about three inches in length. ,.... Measurements in millimetres of specimens of Gagata cenia (Ham.). c.o ...... ~ Chutri Gouri Calcutta and Barhat and Chenab ~ Manipur, Assam. in Terai, Nawabgunge, Damodar River, Orissa. Delhi. Canal, Nepal. Bengal. Bihar. Punjab. A A f , ~ ,----"- , f \ ~ Standard length 56·5 59·5 65·0 72·5 84·5 59·0 77·0 63·5 38·0 42·5 159·0 63·0 42·0 55·0 66·0 78·5 52·0 rn Length of head 14-0 15-0 15·5 18·0 23·0 16·2 20·5 17·5 8-5 11-0 16-0 17-0 11·5 15·0 18·2 21·5 14·0 Height of head at occiput 10·0 10-0 12·0 11·5 13·5 10·0 12-5 10·0 5·5 6·0 8·5 9-5 6-5 8·5 11-0 12·0 7·5 ~ Il:l 0 :id Width of head 8-5 9-0 11·0 10·5 13-0 9-0 11-5 9·2 5·5 6·0 8·5 9·0 6·0 7-5 9·2 11·2 8-0 ~ Length of snout 5·5 5·0 5·5 7-0 8-0 5·5 8·0 6·0 3·0 3-5 6-0 7·0 4-5 5·0 7-2 8-0 6-0 ~ Diameter of eye 6·5 8-0 7-0 7·5 7·0 5·5 6·0 5·5 3-5 4·0 5-5 7·0 4-0 6·0 6-5 7-0 5·0 ~ Interorbital width 4-0 4·0 4·0 5·5 6-0 4-0 5-0 4·0 2-5 2-0 3-5 4·0 2·8 3-5 3-5 5·0 3·0 P Depth of body 11·0 12-0 14-0 14·0 17·0 10·0 13-0 12·0 6·5 8'5 10·5 10·5 10·5 9·5 11·4 13-5 10·0 t-t Length of caudal peduncle 8·0 8·5 9·0 8·5 10·0 8·0 11·0 7·5 5·0 6-0 8·0 7·0 7,0 7·5 9·0 10·0 6-5 ~ ~ ~ Least height of caudai peduncle 5·0 5·0 6·0 6·5 7·0 5·0 5'5 5·0 3·5 4·5 4·5 5-5 4-0 3·5 5·5 6·5 3-5 ~. Longest ray of dorsal 12·5 14-0 15-0 14·5 22·5 14·0 17-0 13-0 8-5 11·0 13·0 13·5 10·5 11·5 13·5 16·0 11·0 ~ Length of dorsal spine 11·0 11·0 12·0 D. 15-5 11-0 15·0 12-0 7-5 9-5 11-5 12-0 9-5 9-5 13-0 14·5 10·0 d ~ ~ Length of pectoral 15·0 15·0 16·0 D. 20·5 13·0 18·0 13·0 8·5 12·5 12·0 14·5 10·0 11·5 15·5 17·5 11·5 CI;I" ~ Length of pectoral spine 12-0 13·5 14·0 D_ 18·0 11·5 17·5 12·5 8·0 10·0 13·0 14-0 9·5 11·0 14-0 17-{) 10-5 ~ Length of ventral 8·5 10·0 11'0 12·5 14·0 9·0 11·0 9'5 6·0 7'0 12·5 9-5 6·0 7'S 10'5 12'0 7'5 \;f;) ~ ...... Longest ray of anal 10-5 10-5 12·0 14-0 14'5 9·5 10-5 9·5 9·0 8·5 10·0 10·0 7·0 7·0 11·0 12·0 8·0 ~ 9-0 11-5 11,0 ~ Length of base of anal 9·0 11·0 13·0 8·5 8·5 9·5 9·0 9·0 9·5 6'0 8·5 9·0 9·5 8·5 ~" Length of base of adipose 9·0 8·5 8·5 12·0 10·5 8·0 10·0 6·5 4·5 6·0 7·0 8-5 6·5 6-5 8·5 10·5 8-0 dorsal. ~ Width of isthmus 1-0 1-2 D. 1-0 3·0 3-5 3·5 3·0 0-8 1-0 1-0 2-5 1·5 3-0 2·5 3-0 2-0 ~ 24 Records of the Indian Museum. [VOL. XLIII, Gagata viridescens (Hamilton). Plate I, figs. 7, 8. 1822. Pimelodu8 viridescens, Hamilton, Fish. Gange8, pp. 173, 376, pI. x, fig. 56. 1854. Pimelodus viridescens, Bleeker, Verk. Bat. Gen. XXV, p. 58. 1877. Nangra punctata, Day, Fish, India, p. 494, pI. cxv, fig. 8. 1877. N angra viridescens, Day, Fis/t. India, p. 494, pI. exv, fig. 7. 1889. lVangra punctata, Day, Faun. Brit. Ind. Fish. I, p. 212. fig. 76. 1889. Nangra viridescens, Day, Faun. Brit. Ind. Fish. I, p. 212. D. 1/6; A. 2/9; P. 1/8; V 1/5; C. 21. In Gagata vifridescens the head ~nd the body in front of the anal fin is greatly depressed and the ventral surface is flattened. The tail is somewhat compressed and subcylindrical. The dorsal profile is slightly arched, while the ventral profile is straight and horizontal in front of the anal fin. The head is large and broad, it is covered with minute spine-like structures; its length is contained from 3·00 to 3·18 times in the standard length. The height of the head is contained from 1·63 to 1·78 times and its ,vidth from 1·27 to 1·31 times in its length. The snout is broad and rounded in front; it projects beyond the mouth for a con siderable distance. The eyes are of moderate size and dorso-Iateral in position; they are not visible from the ventral surface. The eyes are relatively larger in young specimens and are situated almost in the middle of the length of the head; their diameter is contained from 3·50 to 4·16 times in the length of the head and from 1·37 to 1·75 times in the length of the snout. The interorbital distance is equal to the dialneter of the eye. The nostrils are well-formed, rounded apertures; they are situated much nearer to the tip of the snout than to the eyes. The median groove on the head is pointed both anteriorly and posteriorly, and extends from in front of the nostrils to the base of the occipital process; behind the level of the eyes there is a slight ridge across the groove. The occipital process is long and club-shaped; its width at the base is contained about 4 tinles in its length; it misses the basal bone of the dorsal fin by a short distance. The mouth is wide, inferior and horizontal; it is provided with fleshy lips which are continuous at the angles of the mouth. The anterior lip is papillated, and both the lips at the angles of the mouth are plicated. The posterior lip is also somewhat roughened along its middle part. The teeth are small and villiform; they are arranged in bands in the jaws. There are four pairs of barbels; the nasals are minute or rudimentary and are liable to be overlooked altogether; the maxillary barbels are consider a.bly shorter than the head, are provided with stiff basal portions which Ee in lateral grooves; the mandibular barbels are much shorter and t.heir bases are situated wide apart, those of the inner pair are con siderably in advance of those of the outer pair. The gill-openings are wide and extensive; the gill-nlembranes are confluent with each other and with the isthmus in the mid-ventral line. The width of the isthmus IS very narrow. The depth of the body is contained from 4·45 to 4·54 times in the standard length. The least height of the caudal peduncle is contained 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 25 from 1·63 to 1·71 times in its length. The portion of the body where the air-bladder comes directly in contact with the skin is not well marked externally. The cubito-humeral processes are well developed. The external urino-genital organs are similar to those described in G. gagata (vide supra, p. 16). The dorsal fin is short and low, and is situated wholly in front of the pelvics; it is considerably shorter than the head and is provided with a small, strong spine, which is smooth along both the borders. The adipose dorsal is short, but well marked; the length of its base is almost equal to that of the rayed dorsal. The paired fins are hori zontally placed; the pectorals are shorter than the head and provided with a very strong spine which is smooth along the puter border, but .is strongly denticulated internally. The pectorals are separated from the ventrals by a considerable distance. The pelvics are small and pointed and extend beyond the anal opening. The caudal fin is deeply forked, with both the lobes pointed and subequal. Hamilton stated that in his Pimelodus viridescens "The sides arr silver coloured, the belly livid, and the fins of the back and tail spotted." The ba.ck is noted to be " reddis'h-brown, crossed by three green bars; and with opaque spotless sides" Day described the colouration of his N angra punctata as follows: "coppery, glossed with gold on the sides : a black blotch on occiput~ and three or four along the back descending half way down the sides. A black band on dorsal, and some bla.ck markings on the caudal." In his N. viridescens, which seems to repre sent young specimens, the colour is "glossy greenish-brown on the back, with two very light green bands passing one from the base of either dorsal fin to the middle of the depth of the body. A dark band on the dorsal fin and spots on either lobe of the caudal" In a young specimen, 44·5 mm. in standard length, besides the two short bands mentioned by Day, there are two other, one obliquely passing through the posterior part of the head and another on the back in front of the base of the caudal fin_ The colouration of the larger specimen corres ponds fairly closely with that of Day's N. punctata. Distribution.-Hamilton described this species from the rivers of the northern parts of Bengal, but Day noted" Rivers of Northern Bengal, not uncommon in the Jumna at Delhi, and also found at Poona in the Deccan" The two specimens we have referred to G. viridescens are from Bengal and Assam respectively and we doubt whether the range of this species extends to the Deccan_ Measurements in millimetres. Tezpur, Assam. Barakar, Santa} Parganas. Standard length 75·0 44·5 Length of head 25·0 14·0 Height of head at occiput 14·0 8·5 Width of head 19·0 11·0 Length of snout 10·5 5-6 Diameter of eye 6·0 4·0 Interorbital width 6-0 4-0 Depth of body 16·5 10·0 Length of caudal peduncle 9·0 6·0 o 26 Records of the Indian Museum. [VOL. XLIII, M eaSU'lements in millimet'les. Tezpur, Assam. Barakar, Santal Parganas. Least height of caudal pedunclo 5·5 3·5 Longest ray of dorsal 15-5 8·0 Length of dorsal spine 9-5 6·5 Length of pectoral .. 18-0 12·5 Length of pectoral spine 16-0 11·0 Length of ventral 12-0 7·0 Longest ray of anal •. 14-5 8·5 Length of base of anal 9-0 6·5 Length of base of adipose dorsal 9-5 6·5 Gagata nangra (Hamilton). Plate I, figs. 9, 10. 1822. Pimelodus nangra, Hamilton, Fish_ Ganges, pp_ 193, 378, pI. xi, fig. 63_ 1854. Pimelodus nangra, Bleeker, Verh. Bat. Gen. XXV, p. 58. 1871. Macrones nangra, Day, Proc. Zool. Soc. London, p.,288. 1877. Nangra buchanani, Day, Fish. India, p. 494, pI. cxiii, fig_ 3. 1889. Nangra buchanani, Day, Faun. Brit. Ind. Fish. I, p. 211. D. 2/9-10 ; A. 3/10 ; P. 1/9 ; V 1/5; C. 16-17. Gagata nangra is a small and slender species in which the dorsal profile is slightly arched, while the ventral profile is horizontal in front of the pelvic fins and thence rises gradually to the tail. The body is compressed from side to side, more so in the tail region. The ventral surface of the head and the anterior part of the body are flattened. The head is sharp, long and oval; its length is contained from 3·83 to 4·18 times in the st.andard length. The height of the head is con tained 2·0 times and its width from 1·06 to 1·50 times in its length. The snout is long and pointed, and projects in front of the mouth for a CQD siderable distance. The eyes are relatively small and dorsa-lateral in position ; they are not visible from the ventral surface. The diameter of the eye is contained from 5·38 to 6·00 times in the length of the head, 1·20 times in the length of the snout and from 1·20 to 1·33 times in the interorbital width. The two nostrils of each side are well marked and are placed nearer the tip of the snout than the eye. The median groove on the head is broad and extends from between the nostrils to the base of the occipital process; the lateral edges of the groove are raised into slightly elevated longitudinal ridges. At the sides of the 'groove in the posterior region of the head there are two pairs of fontanels. The occipital process is broad and long; it is almost twice as long as broad a t the base and almost extends to the basal bone of the dorsal fin. The mouth is inferior, crescentic and horizontal; its width is almost equal to the length of the snout. The lips are visible as definite structures only near the angles of the mouth. The teeth are minute and in the upper jaw are situated outside the Inouth. There are four pairs of barbels ; the nasal barbels are almost as long as the he~d ; the maxillary barbels are provided with stiff basal parts and extend to the anal fin or beyond; the outer mandibular barbels are more than one and a half times as long as head wbDe the inner pair is equal to the head behind the nostrils. The bases of the inner pair of mandibular barbels are situated in front of those of the outer pair. The gill-openings are wide 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 27 and on the ventral surface extend anteriorly to the median line; the gill-membranes are united with each other. The depth of the body is contained from 6·90 to 8·37 times in the standard length. The least height of the caudal peduncle is contained from 2·20 to 2·75 times in its length. The portion of the body where the air-bladder comes in contact with the skin is not well marked ex ternally. The cubito-humeral processes are, however, well developed. The commencement of the dorsal fin is situated well in advance of that of the pelvics, but its base extend over the pelvic fins; its longest ray is greater than the head but the spine is somewhat shorter. The dorsal spine is a strong prickle which is smooth along both the edges. The adipose d9rsal is short but well marked. The paired fins are hori zontally placed, they are somewhat shorter than the head and are sepa rated from the pelvic fins by a considerable distance. The pectoral spine is strong and broad; it is smooth along the outer border but is strongly denticulated internally. The pelvic fins are long and pointed; they extend beyond the anal opening but do not reach the base of the anal fin. The caudal fin is deeply forked with both the. lobes sharply pointed. Hamilton noted that the colours of Gagata nangra " are rather agree able, being silver, with some green on the back, and a faint brown streak across the foremost back fin, and another across the fin of the tail" According to Day, the colour is " muddy, with three indistinct vertical greenish half bands" In the specimens examined by us, there is a short, faint longitudinal band below the base of the dorsal fin and another along the lateral line. There is a vertical bar at the base of the caudal fin and the dorsal surface of the head is dusky. Distribution.-Hamilton found this species in the Kosi river, but Day extended its range to the Ganges, Jumna and Indus. The two 8pecimens of G. nang-ra examined by us ,vere collected from the river Hooghly at Nawabgunj. This species can be readily distinguished by its longer barbels, pOInted snout and extensive gill-openings. Measurements in rnillimetres. St.andard length .. 33·5 34·5 Length of head 8·0 9·0 Height of head at occiput 4·0 4·5 \Vidth of head 7'5 6·0 Length of snout •. 1·8 1·8 Diameter of eye •. 1·5 1·5 Interorbital width 1·8 2·0 Depth of body 4·0 5·0 Length of caudal peduncle 5·5 5·5 Least height of caudal peduncle 2·0 2·5 Longest ray of dor~al g·O 10·0 Lengt.h of dorsal spine 7·0 8·0 Length of pectoral 6·8 8·0 Length of pectoral spine 5·2 6·5 Length of ventral 6·0 6·8 Longest ray of anal 7·4 9·5 Length of base of anal 5·0 5·0 Length of base of adipose dorsal 5·5 7·0 02 28 Records of the Indian Museum. [ VOL. XLIII, x. FISHES OF THE GENUS Batasio BLYTH. In the preceding article of this series, attention is directed to the fact that considerable confusion prevails regarding the taxonomic validity and the generic limits of Batasio Blyth, and reference has been made to the more salient features by which it can be distinguished from the superficially allied genus Gagata. In this article we give a detailed historical and taxonomic account of the genus, and descriptions of the species which we assign to it. A new species of Batasio has been dis covered from Travancore, S. India, and the range of one of the Indian species, B. tengana, has recently been extended by Hora and Guptal to the Malay Peninsula. These new records of the distribution of the genus from such widely separated localities are very significant from a zoogeographical point of view and lend considerable support to the hypothesis advanced by one of us2 that the similarity in the fish-fauna of the Malay Region and of South India is due to the migration of the southern Chinese fishes to both the regions along mountain ranges at a time when the geographical features of these countries were different from what they are to-day. The migration of Batasio from Burma and Assam to Travancore was probably along the old Satpura trend of mountains as far as the Western Ghats and thence along the Ghats to the south of the Peninsula. Batasio Blyth. ] 860. Batasio, Blyth, Journ. As. Soc. t Bengal XXIX, p. 149. 1862. 1 Batasio, Bleeker, Atl. Ichthyol. II, p. 9. 1863. ? Batasio, Bleeker, Ned. Tijds. Dierk. I, p. 94. 1921. Macrnnoides, Hora, Rec. Ind. Mus. XXIII p. 179 (1921). In 1860, Blyth3 established the genus Batasio to accommodate a group of Bagroid fishes and characterised it as follows :- " A Bagroid form well worthy of distinction; comprising a number of small species with round and prominent muzzle, and the contracted mouth opening from below: with eight, or sometimes (1) six, cirri, which are very short, the maxillary cirri scarcely passing the eye in some. Palatal band of teeth continuous with the mass of maxillary teeth, or separated only by a slight groove. Rest as in Bagrus (verus). "Type. B. Buchanani, nobis; Pimelodus batasio, H. B." Blyth did not examine any specimen of Hamilton's4 Pimelodus batasio, but described a new species, B. ajJinis, from Tenasserim. He observed that :- "To the same type, but with shorter adipose dorsal, appertain the tenga1Ul, chandamara and rama of Buchanan Hamilton. B. chandarnara is referred to Silun dia by M. Valenciennes, and is described by Hamilton to have only two cirri; but his unpublished figure represents six cirri distinctly, and in all this group the minute cirri are discernible with difficulty and are extremely liable to be overlooked. To Ba{}ru8 capen8es of Sir A. Smith's' Illustrations of S. African Zoology' would ap pear also to be referable to this particular division." Bleeker5 considered Batasio a doubtful genus, but assigned it to the pnalanx Bagrichthyes and stirps Bagrini. Giinther~ evidently regarded 1 Hora, S. J.J. and Gupta, J. C., Bull. Raffles Mus. Sin{}apore, No. 17 (1941). 2 Hora, S. L., Rec. Ind. Mus. XXXIX, pp. 255, 256 (1937) ; Proc. Nat. Inst. Sci. India IV, p. 405 (1938). a Blyth, E., Journ. As. Soc. Bengal XXIX, pp. 149, 150 (1860). 4 Hamilton, F., Fish. Ganges, p. 179 (Edinburgh, 1822). 6 Bleeker, P., Ned. Tijds. Dierk. I, p. 94 (1863). 6 Giinther, A., Cat. Fish. Brit. Mus. V, p. 83 (1864). 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 29 I it as a synonym of Macrones, for he described both Pimelodus batasio Ham. and Batasio affinis Blyth in this genus. Day! included it under Gagata and remarked in a footnote as follows :- "Genus Bataaio, Blyt·h, is said to comprise fishes with the barbels shorter than the head and teeth on the palate, examples: Pimelodu8 batasio, H. B. (the author merely says of the teeth, that those ' in both jaws are crowded '), P. tengana, H. B., B. aJfinis, Blyth, P. rama, H. B. The two first probably belong to genus Gagata, the third to Macronea, and the last two to Lioca8Sis." Vinciguerra2 discussed the systematic position of Batasio in regard to Macrones and other allied Bagrid genera, but did not consider it distinct from Macrones. He described a new species M. dayi from Meetan and Toungoo which is stated to be closely allied to Batasio affinis Blyth. Jordan in his' Genera of Fishes' (p. 294) stated that Batasio Blyth replaces Gagata Bleeker. In view of the confused taxonomic position of Batasio~ one of us (S. L. H.) did not realize its generic limits when he created the subgenus Macronoides3 for Macrones affinis (Blyth), M. dayi Vinciguerra and M. marianiensis Chaudhuri. 4 Macronoides was characterised as follows :- "This new subgenus is proposed for species which differ from typical Mac rone8 in the possession of a distinct ventral mouth bordered by fringed lips; in hav ing short barbels not exceeding the length of the head; in the mandibular pairs of barbels being disposed in a transverse row across the mandible and in the pos session of open pores on the ventral surface of the head just behind the mouth. In general facies the fish of this subgenus show a remarkable resemblance to those of the genus Gagata, from which, however, they are easily distinguished by the crescentic band of teeth and a free air-bladder in the abdominal cavity." In examining the collection made by Messrs. G. E. Shaw and E. O. Shebbeare from the Terai and Duars, one of us (S. L. H.) found repre sentatives of Hamilton's little known species-Pimelodus batasio-and found it to belong to his genus Macronoides. He, therefore, suggested to Shaw & Shebbeare6 to revive Blyth's genus Batasio and to describe this fish as Batasio batasio (Hamilton). Having cleared the systematic position of Batasio Blyth from a study of the fresh material of B. batasio (Ham.) obtained from its type locality, we may now consider which other species can be assigned to this genus. We have indicated above (vide supra, p. 13) that Hamil ton's Pimelodus tengana, 6 as surmised by Blyth already (vide supra, p. 28), belongs to this genus. In a recent collection made by one of us (S. L. H.) from the Terai and Duars there are several specimens which are referable to this' species, though the colouration, which is variable, differs from that described by Hamilton. He observed that :- " ...... The body is diaphanous, with a silver coloured membrane invest. ing the viscera ~nd spine, and with a gloss of gold on the sides. On the back are many black dots, which are collected into a spot above each pectoral fin, and also on the crown of the head. The fins of the back and tail also are dotted, so that the edge of the last is black, and several spots are formed on the first." 1 Day, F., Fish,. India, p. 492 (1877). 2 Vinciguerra, D., Ann. Mus. Giv. Store Nat. Genova (2) IX, pp. 211-217, 230·235 (1890). 3 Hora, S. L., Bee. Ind. MU8. XXII, p. 179 (1921). 'Chaudhurj~ B. L., Bee. Ind. Mus. VIII, p. 253, pl. xi, figs. I, la, Ib (1913). 6 Shaw, G. E. and Shebbeare, E. 0., Journ. Roy. As. Soc. Bengal, Science l.lI, pp. 97. 98, text-fig. 98, 1937 (1938). 6 Hamilton, F., Fisk. Ganges, p. 176, pl. xxxix, fig. 58 (Edinburgh, 1822). 30 Records of the Indian Museum. [VOL. XLIII, Hamilton found this species in the Brahmaputra river at Goalpara. In the adult specimens from the Terai and Duars the colouration is mo~e or less similar to that described by Hamilton but in the younger specI mens the body is marked with a few oblique bands and spots, and the distal half of the anterior rays of the dorsal fin is black. On the whole the colour seems to vary considerably with age (vide infra, p. 38). In describing Batasio affinis, Blyth! remarked :- "Exceedingly like B. Buchanani, as described by Buchanan Hamilton and as figured in one of his unpublished coloured drawings; whereas his published fig~re (F. G. pI. xxiii, f. 60) refers to his Pimelodu8 carcio, which is a true Bagrus wI~h moderately long maxillary cirri :-but. having 12· instead of 16 anal rays, no diS tinct longitudinal black stripe on each side. of the body, but a tendency to show three or four black broad cross-bands, more or less distinct, besides a round black spot near the gill-covers, as in the other. The first dark band proceeds obliquely downwards from the fore-part of the first dorsal, to some distance below the lateral line; and posterior to this first band are obscure traces of three or four others, the last at base of tail. On the membrane of the dorsal fin is a large blackish spot, consisting of minute dark specks." The type of Blyth's species is preserved in the collection of the Indian Museum, and though its colouration has faded there can be no doubt of its identity with the specimen of Hamilton's Pimelodus tengana from the Tista River System. In his 'Supplement' to the 'Fishes of India' (1888, p .. 805), Day described Leiocassis fluviatilis, a species of freshwater fish found by Day in Col. Tickell's "volume of beautiful coloured drawings of Burmese Fishes with their descriptions", of which Col. Tickell is stated to have "obtained four examples, the largest 3! inches long from the Anin, a steam rising near Weywoon, Wagroo in the Tenasserim Provinces ". The identity of this species is still in doubt, but recently Hora and Gupta examined six specimens from the Chenderoh Lake, Perak, in the collection of the Raffles Museum, Singapore, which they referred to this species. The most characteristic feature of L. fluviatilis is its colouration, which, according to Day (loc. cit.), is as follows :- " Yellowish horny with darker shades of olive brown on the snout and along the back, also some cloudy markings. A large black blotch on the lateral-line above the anal fin, another between the pectoral and first dorsal. Tip of dorsal and ends of both caudal lobes black." In the examples from Perak the black blotch on the lateral line above. the anal fin is very conspicuously marked, while the anterior blotch re presents the area against which the air-bladder comes directly in con tact with the skin. Another conspicuous feature of these examples is an oblique horseshoe-shaped band lying in front of the first dorsal fin and descending on the sides to below the lateral ,line. Sometimes this band breaks up into a dorsal blotch and two oblique bars on the sides. There is a submarginal band on the dorsal fin and the tips of the caudal fins are somewhat dusky but not black. Day observed that with the exception of the maxillary pair of barbels no others were detected. We find that there are two pairs of mandi bular barbels, the outer being more or less equal to the diameter of the eye while the inner are very rudimentary. The nasal barbels extend 1 Blyth, E., Jo'Urn. As. Soc. Bengal XXIX, p. 149 (1860). 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 31 to the front border of the eye or slightly beyond it. The maxillary barbels, as noted by Day, extend as far as the posterior border of the orbit. A comparison of the Perak examples with those of Pimelodus tengana from the Eastern Himalayas and of Batasio affinis from Tenasserim leaves little doubt of their identity. We are, therefore, led to conclude that Day's Leiocassis fluviatilis is a synonym of Batasio tengana (Ham.). Vincigeurra'sl Macrones dayi is stated to be closely allied to Leio cassis fluviatilis Day and Batasio ajJinis Blyth, only differing in pro ... portions and colouration. From a study of a large number of speci mens we have found that such differences have no specific value and we are of opinion, thfrefore, that M. dayi is also a synonym of Batasio tengana (Ham.). Chaudhuri's2 M. marianiensis, described from the Brahmaputra River System, Assam, and later recorded from the streams at the base of the Eastern Himalayas, is also a synonym of B. tengana. The species described, and figured by Shaw and Shebbeare3 as Leiocassis rama is also referable to B. tengana. Regarding this species Shaw and Shebbeare noted :- "In general appearance resembles those species of Mystus which have a shoul der-blotch and longitudinal bands but has much shorter barbels. It therefore somewhat resembles Batasio batasio from which it is distinguished by having a shorter adipose fin and a longer anal." Recently we obtained a number of specimens from Travancore in which the body is of deep gray colour and is devoid of any transverse oblique bands or spots. These specimens are of a somewhat larger size and on morphological characters represent a new species of Batasio. In the present-day discontinuous distribution of this genus we have another record of the common origin of the fauna of the Malay Peninsula and that of Peninsular India. Besides Batasio batasio (Ham.) and B. tengana (Ham.), there are two other species of Hamilton's Pimelodus which have been assigned by Blyth to Batasio, viz., P. chandramara and P. rama. Hamilton4 recognised the great similarity betweerJ. these species and separated them on the following characters:- P. ckandramara. P. rama. 1. Two barbels. 1. Six barbels. 2. Diaphanous with clusters of black dot.s ; 2. Diaphanous, yellowish without dots. golden stripe along lateral line. Black spot on nape, divided into four lobes. 3. A. 17. 3. A.15. As pointed out by Blyth, Hamilt()n's original figure of P. chandl'a mara5 shows six distinct barbels. The uther two points of difference are not of specific value as the colour may vary according to habItats 1 Vinciguerra, D., Ann. Mus. Civ. Store Nat. Genova (2) IX, p. 230 (1890). 2 Chaudhuri, B. L., Ree. Ind. Mus. VIII, p. 253, pI. xi, figs. 1, la, Ib (1913). 3 Shaw, G. E. and Shebbeare, E. 0., Journ. Roy. As. Soc. Bengal, Science III, p. 90 text-fig. 88, pI. 3, fig. 4, 1937 (1938). 4. Hamilton, F., Fish. Ganges, pp. 162, 176 (Edinburgh, 1822). I; Vide Hora, S. L., Mem. Ind. Mus. IX, pI. xxi, fig. 6 (1929). 32 Records of the Indian Museum. [VOL. XLUl, and the difference in th~ number of anal rays may be due to individual variation. Both the species were deE'cribed from Northern Bengal.I Hamilton's de..<::criptious of both the species are brief and inadequ~te for their specific determination, and, as pointed out by Blyth (loc. c~t.), there are discrepan.cies between his descriptions and figures. For ms tance, Hamilton stated in his description that P. chandramara pos sesses only " two tendrils", whereas in his unpublished figure 6 barbels are distinctly shown. The consideration of the number of barbels alone seems to have led Swainson2 and Ouvier & Valenciennes3 to refer P. chandramara to the genera Si10nia and Silundia respectively. .It may be stated without any fear of contradiction that Hamilton's specIes does not belong to either of these genera. Blyth placed it in the genus Batasio but without examining any specimen of the species; his con clusion seems to have been based on a study of the unpublished drawing of the species. In the two species of Batasio referred, to above, there is a distinct nasal barbel, which is neither described nor shown in the figure of Pimelodus chandramara. Giinther4 referred P. 'fa'tna very doubtfully to the genus Rita, but considering the large size of its eyes, general facies and habitat, it is difficult to place it among Rita. Day5 examined a specimen from Assam, which undoubtedly belongs to this species and regarded it as Leiocassis. 6 On a careful analysis of Day's description it is found that the species shows affinities with both Batasio and Leiocassis. For instance, the subcutaneous nature of the eyes is a character of Leio(!assis, but their relatively large size is a cha racter of Batasio. The absence of the nasal barbels, however, precludes it from either of the genera. We have examined Day's specimen from Assam, which is in a poor state of preservation, and have found open pores along the lower jaw and edges of the gill-covers which are charac teristic of Batasio. In view of what is stated above, and in the absence of good and reliable material it is perhaps desirable to keep Pimelodus rama in a separate genus for which Bleeker has already proposed the name Rama. In 1931, H. M. Smith? described from Siam a strikingly marked little catfish and referred it to the genus Mystus. The colouration and general build of this species, M. havmolleri, are very similar to 1 Day (Fish. India, p. 452, 1877) notes that" In Ham. Buch. MSS. P. chandra mara is said to be found in the Rangpur district in the Mahananda and also in the Di najpur district. In Purniah he records it as termed Thunka-patasl of the Kus! and K.hiLma'iri at Bholahat. In t.he 'Fishes of the Ganges' , he remarks that P. rama is from the Brahmaputra. The fish I have here described from the same locality, appears to be a link between the two forms, as the Assam one is said to have on nape a large black spot divided into four lobes, and which is not present in my specimens, which it is said to differ from P. ckandramara. chiefly in the latter being deficient in this mark. I have referred my specimen to P. rama as it came from Assam. 2 Swainson, W., Nat. Bist. Classification Fish. Amph. Rept. II, p. 305 (1839). 30uvier, G. ~nd Valenciennes, A., Bist. Nat. Poiss. XV, p. 49 (1840). 4. Gunther, A., Cat. Fish. Brit. Mus. V, p. 92 (1864).- 6.Day, F., Fisk. India, p. 451 (London, 1877). 6 Regan [Ann. Mag. Nat. Bist. (8) II, p. 547,1913] observed that" Pimelodus rama IJam. Buch., from Bengal and Assam, is placed by Day in Lioca8Sis (Fish. India, p. 451 pl. cxv, fig. 2) ; it seems improbable that this little fish really belongs to the genus; but if it does, the large eye and minute mandibula.ry barbels distinguish it from all the other species". 7 Smith, H. M., Proc. U. 8. Nat. Mus. LXXIX, Art. 7, p. 24, fig. 24 (1931). 1941.] s. L. HORA & N. C. LAW: Siluroia Fishes of India. 33 l!a~asio tengana, though in the size of its eyes, barbels and adipose dorsal It IS somewhat different. It is stated to be provided with "a trans v~rse row of 4 large pores behind lower lip; entire· snout thickly beset wIth minute pores" A more detailed description of the species is ne cessary to determine its precise specific limits but there can hardly be any doubt of its position in the genus Batasio. In fact, its resflmblance to B. tengana is so close that, in the present state of our knowledge we consider that the differences between the two are not of specific value. From the above\ it will be clear that in the present statfl of our know ledge only three Indian species can definitely be assigned to the genus Batasio. These can be distinguished by the following key:- Key to the Ind'l~an species QfBatasio Blyth. A. Base of adipose dorsal considerably longer than that of anal. 1. Body marked with longitudinal bands; a con spicuous dark spot above pectoral. [Me dian gro,Ove on head continued on occipital process for some distance; occipital process extending over basal bone of dorsal and meeting first dorsal spine; no pores on dor- sal surface of head.] . . B. batasio. II. Body without longitudinal bands or spots. [Median groove on head extending to base of occipital process ; occipital process sepa rated from basal bone of dorsal fin by a considerable distance; pores on dorsal sur- face of head present] . . B. travancoria. B. Base of adipose dorsal shorter or equal to base of anal. [Median groove on head extending to end of occipital process and in its posterior portion containing basal bone of dorsal fin; no pores on dorsal surface of head ; body marked with oblique vertical bands or spots.] B. tengann .. Batasio batasio (Hamilton). Plate II, figs. 4-6. 1822. Pimelodu8 batasio, Hamilton, Fish. Ganges, pp. 179, 377. (The drawing on pI. xxiii, fig. 60 does not refer to this species, but to P. carcio described-on p. 181). 1839. Bagru8 batasio, euvier and Valenciennes, Hist. Nat. Poiss. XIV, p. 425. 1860. Batasio Buchanani, Blyth, Journ. As. Soc. Bengal XXIX, p. 150. 1862. ? Batasio Buchanani, Bleeker, Atl. lchthyol. II, p. 8. 1863. ? Batasio Buchanani, Bleeker, Ned. Tijdscltr. DierJcund. I, p. 94. 1864. Macrones batasio, Gunther, Gat. Fish. Brit. Mus. V, p. 83. 1877. Gagata batasio,Day, Fish. India, p. 493, pI. xcix, fig. 5 (Hamilton's MS. drawing reproduced). 1889. Gagata batasio, Day, Faun. Brit. Ind. Fish. I, p. 209. 1929. PimelodU8 batasio, Hora, Mem. Ind. Mus. IX, pI. xxii, fig. 3. 1938. Batasio batasio, Shaw and Shebbeare, Journ. Roy. As. Soc. Bengal, Sc·ience III, p. 97, fig. 98. D. 2/7; A. 3-4/9-10; P. 1/5-8; V 1/5; C. 17. Batasio batasio is a medium-sized species in which the dOfr-m.l and the ventral profiles are moderately arched. The dorsal profile rises gradually from the tip of the snout to the origin of the dorsal fin when.ce it slopes 'down gradually to caudal peduncle where it is horizontal The ventral profile is horizontal and flattish just' for a short distance between the head and pelvic fins, thence it rises gradually towards 34- Records of the Indian Museum. [VOL. XLIII, both ends. The body is compressed from side to side, more so in the tail region. The head is sharp, bluntly pointed and conical; its length is con tained from 3·61 to 3·90 times in the standard length. The height of the head is contained from 1·34 to 1·71 times and its width from 1·43 to 2·38 times in its length. The snout is fairly long and pointed; it projects in front of the mouth for a short distance. The eyes are of a nloderate size and dorso-Iateral in position; they are not visible from the ventral surface. The orbital Inargins are free. The diameter of the eye is contained from 2·63 to 3·30 times in the length of the head, from 1·14 to 1·53 times in the length of the s~out and from 0·71 to 1·20 Text-fig. 2.-Alimentary canal, dentition and air-bladder of Batasio batasio (Hamil ton). a. Alimentary canal: X 21. b. Dentition: X 12. c. Air-bladder: X 21. times in the interorbital width. The two nostrils of each side are wide apart and are not so conspicuous as in the species of Gagata. The anterior nostril is placed above the base of the maxillary barbel and Inuch nearer the tip of the snout than the eye; while the second pair is tcloser to the eye than to the anterior nostril. The median groove on the head is long and narrow; it extends from between the posterior nostrils to one-third of the occipital process; the lateral edges of the groove are slightly raised into longitudinal ridges. In the groove, 1941.] S. L. flORA & N. C. LAW: Siluroid Fishes of India. 35 there are two fontanels which are separated by a broad bony ridge; the anterior fontanel extends over the anterior two-thirds of the eye, while the posterior fontanel comluences from behind the eye and ex tends for a short distance over the occipital process. The occipital process is long and broad; its length is almost 3! times its width at the base; it extends over the basal bone of the dorsal fin. The mouth is inferior, crescentic and horizontal; it is bordered by fleshy lips which are continuous at the angles of the mouth. The labial groove is broadly interrupted in the luiddle ; both the lips are distinctly fimbriated. Be hind the lower lip there are four slit-like openings and four pairs of pores on the ventral surface of head running obliquely froin the mandi bular barbels to the gill-openings. The teeth are small and villiform; they are arranged in broad continuous bands in the jaws and in a similar band on the palate. There are four pairs of barbels; the nasal barbels, which are placed at the anterior end of the posterior nostrils, are small and considerably shorter than the diameter of the eye; the nlaxillary barbels do not extend beyond the posterior margin of the orbit and the mandibular barbels are still shorter; the bases of the latter are not situated exactly in a transverse line behind the lower lip, but those of the inner pair are slightly in advance of those of the outer. The gill-membranes are llotched anteriorly and the gill-openings are very extensive. The depth of the body is contained from 3·72 to 4·40 times in the standard length. The least height of the caudal peduncle is contained from 1·33 to 1·57 in its length. The portion of the body where the air-bladder comes in contact with the skin is well marked externally. The cubito-humE'ral processes are also well developed. The external features of the urino-genital organs are similar to those as described above in the species of Gagata (vide supra, p. 16). In ripe males the urinogenital papilla is well marked. The rayed dorsal fin is situated well in advance of that of the pel vics, but its base extends almost over the pelvic fins; its longest ray is shorter than the length of the head and the spine is much shorter. The dorsal spine is a strong prickle which is smooth along both the borders. The adipose dorsal is considerably long and well marked; the length of its base is equal to or greater than the length of it~ head. The pectoral fins are horizontally placed and are shorter than the head; they are separated from the pelvic fins by a considerable distance. The pectoral spine is strong and broad; it is smooth along the outer border but is strongly denticulated internally. The pelvic fins extend beyond the anal opening but do not reach the base of the anal fin. The caudal fin is deeply forked with both the lobes sharply pointed. Hamilton noted that the fish is provided " with a diaphanous body, having on each side two stripes dotted with black The cavity containing the viscera is lined with a silver coloured membrane; and, besides the two stripes, the fish has on each shoulder a spot conl posed of black dots. The first dorsal fin is spotted, the second is dotteu." Shaw and Shebbeare described the colouration as follows :- " I..leaden above, yellow beneath. A dark longitudinal band along the lateral line expanding in~o a shoulder-blotch immediately below tho dorsal fin. A second fainter a.nd somewl1at curved dark ba.nd midway between the lateral lino and the 36 Records of the I rulian M meum. [VOL. XLllt, dOTsal ridge, commencing at the top of the opercle and ending about the middle of the adipose fin. It is connected with the dark colour of the dorsal ridge at the front part of the rayed dorsal." Distribution.-Batasio batasio is known so far from the Tista River System. 'Ve ha ve examined several specimens from the streams of Terai and Duars. Measurements in millimetres. Standard length 55·0 65·0 69·0 75·0 84·0 89·5 Length of head 14·5 18·0 19·0 20'5 21'5 23·0 Height of head at occiput 9·5 10·5 13·0 14·0 16·0 15·0 Width of head 9·0 10·0 12·5 13·8 9·0 16·0 Length of snout 6·5 7'5 8·0 8·0 10·0 10·0 Diameter of eye 5·5 6·0 7·0 7·0 6·5 7·0 Interorbital width 4·5 5·0 5·0 5·0 6·0 6·5 Depth of body 12·5 15·0 18·5 17·5 23·5 23·0 Lengt.h of caudal peduncle 8·0 9·0 11·0 11·0 12·5 12·0 IJcast height of cR-udal peduncle •. 5'5 6·5 7·0 8·0 8·5 9·0 Longest ray of dorsal 10·0 11·5 13·0 14·0 D. 14·5 Length of dorsal spine 9·0 12·0 9·5 12·0 D. D. Length of pectoral .. 11·0 12·0 14·0 13·0 14·5 14·0 Length of pectoral spine 10·0 11·0 12·0 D. 13·0 13·0 Length of vt'ntral 8'5 12·0 10·0 11·0 10·5 13·0 Longest ray of anal .. 11-0 9·5 9·5 11·5 15·5 D. Lengt,h of base of anal 10-5 10·0 12-0 11-5 14-5 11-0 I .. ength of base of adipose dorsal 19·0 16·5 19·0 22·0 21·5 23·0 Batasio tengana (Hamilton). Plate II, figs. 1-3. 1822. Pirnelodu8 tengana, Hamilton, Fi8h. Ganges, pp. 176, 377, pI. xxxix, fig. 58. 1839. Bagrus tengana, Cuvier & Valenciennes, Bist. Nat. POi88. XIV, p. 433. 1854. Bagrus tengana, Bleeker, Verk. Bat. Gen. XXV, p. 56. 1860. Batusio affini8, Blyth, Journ. A8. Soc. Bengal XXIX, p. 150. 1860. Bata8io ,tengana, Blyth, Journ. A8. Soc. Bengal XXIX, p. 150. 1864. J.llacrone8 aJlinis, Gunther, Gat. F'i8k. Brit. Mus. V, p.83. 1864. J.llacrones tengana, Gunther, Gat. Fish. Brit. MU8. V, p. 84. 1873. Macrones aJfinis, Day, Proc. Zool. Soc. London, p. Ill. 1877. ~lacrone8 Blythii, Day, Fi8h. India, p. 445. 1877. Gagata tengana, Day, Fish. India, p. 493. 1888. Leiocus8is jluviatilis, Day, Fish. India Suppl., p. 805. 1889. LioCU8Sis jluviatili8, Day, Faun. Br'it. Ind. Fi8k. I, p. 164. 1889. Jtlacrones blythii, Day, Faun. Brit. Ind. Fisk. I, p. 151. 1889. Gagata tengana, Day, Faun. Brit. Ind. Fish. I, p. 210. 1890. Macrones Dayi, Vinciguerra, Ann. MU8. Giv. Store Plat. Genova (2) IX p. 230, pI. vii, fig. 3. ' 1913. Macrone8 marianienBi8, Chaudhuri, Bec. Ind. Mus. VIII, p. 253, pI. xi, figs. I, la, lb. 1921. Macrones (Macronoide8) aJlini8, Hora, Bee. Ind. Mus. XXII, p. 180. 1921. Macrones (Macronoide8) meria,niensis, Hora, Bee. Ind. Mus. XXII, p.736. 1931. Mystus havmolleri, H. M. Smith, Proe. U. S. Nat. Mus. LXXIX, art. 7, p. 24, fig. 12. 1937. Leiocassis 'I'ama, Shaw & Shebbeare (nec Hamilton), Journ. Roy. Asiat. Soc. Bengal, Science III, p. 90, text-fig. 88, pI. iii, fig. 4. 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of India. 37 D. 2/7-8; A. 3-4/8-11 ; P. 1/7-9 ; V 1/5; C. 16-18. Batasio tengana is a small, well-built species in which both the dorsal and the ventral profiles are somewhat arched; the body is deepest .about the commencement of the dorsal fin and from that point it tapers both anteriorly and posteriorly. The ventral surface between the pectorals is only slightly flattened, but that of the head is fl~ttish. The fish is compressed from side to side; this is more marked in the tail region. The head is broadly pointed anteriorly and the snout is produced beyond the mouth for a short distance. The length of the head is con tained from 3·58 to 4·17 times in the standard length; the height of the head is contained from 1·3-5 to 1·78 times and its breadth from 1·36 to 1·70 times in its length. The eyes are of a moderate size and are dorso-Iateral in position·; they are not visible from the ventral surface, and are situated almost in the middle of the length of the head. The diameter of the eye is contained from 2·50 to 3·40 times in the length of the head and from 0·87 to 1·4 times in the length of the snout. The interorbital distance is considerably less than the diameter of the eye. The nostrils are situated wide apart; the anterior nostril is tubular and directed forwards; the posterior nostril is situated almost midway between the eye and the tip of the s:qout and is provided with a nasal barbel at its anterior end. The median groove on the head is long and narrow; it extends from behind the posterior nostrils to the end of the occipital process; its margins form slightly elevated ridges. In the groov~, there are two median fontanels which extend to the base of the occipital process and are separated from each other by a narrow ridge situated behind the eyes. The anterior part of the basal bone of the dorsal fin is lodged in the median groove of the occipital process, which is long and narrow. The mouth is small, inferior, horizontal and crescentic; it is bordered by fleshy lips :which are continuous and pendulous at the corners of the mouth. THe labial groove is broadly interrupted in the middle; both the lips are ~istinctly fimbriated. Be hind the lower lip there are five slit-like oval openings and four pairs of small round holes situated obliquely between the bases of the lnandi bular barbels and the gill-openings. The teeth are small and villi form; those in the jaws form oval patches while those on the palate form a lunate band. There are four pairs of barbels; the nasal barbels extend to the anterior border of the orbit or a little farther; the maxil lary barbels are the longest but are just about half the length of the head and the mandibular barbels are considerably shorter. The ba~es of the mandibular barbels are situated at a considerable distance be hind the mouth and are not in a straight line, those of the inner pair being somewhat in advance of those of the outer. The gill-openings are very extensive and the gill-membranes are deeply notched ante- riorly. The depth of the body is contained from 3·69 to 4·65 tilnes in the standard length. The least height of the caudal peduncle is containp.d from 0-84 to 1·60 times in its length. The portion of thc hody where the air-bladder comes in contact with the skin is well-luarkccl. The cub ito-humeral processes are narrow and can be readily felt through 38 Records of the I ndian Museum. [VOL. XLIII, the skin. The external features of the urinogenital organs are similar to those of Batasio batasio. The rayed dorsal fin is situated consideraqly in advance of the pelvic fins, but its base extends almost over their commencement. The longest ray of the dorsal fin is considerably shorter than the head and the spine is still shorter. The dorsal spine is a smooth, moderately strong prickle. The adipose dorsal, though well marked, is not so extensive ·as that of B. batasio; it commences considerably behind the rayed dorsal and its base is somew hat shorter than the head. The pectoral fins are situated slightly above the ventral surface of the body; they are much shorter than the head and are separated from the pelvic fins by a con siderable distance. The pectoral spine is flattened and strong; it is snl00th externally but strongly denticulated internally. The pelvic fins are shorter than the pectorals and extend beyond the anal opening but not as far as the urinogenital openings. The anal fin is situated below the adipose dorsal and its base is slightly longer than that of the rayed dorsal. The caudal fin is deeply forked, with the lower lobe somewhat better developed; both the lobes are bluntly pointed. As indicated above (vide supra, p. 30), the colour varies consider ably with the size of the specimens and locality. In fresh specimens collected from the streams of Terai and Duars, Tista River System, the general surface is gray-olivace'ous which is deeper above and lighter below. The dorsal surface of the head is dark with an indication of a band in the region of the eyes; this band passes on the sides below the eyes but does not extend to the ventral surface. There is a broad black spot on the nape. Behind the head there is an oblique darkish band dorsally which extends to the sides and joins the black blotches in the region above the pectorals where the air-bladder comes in contact with the skin. The rest of the body is marked with five oblique, saddle shaped bands of varying depth of colour which do not extend to the ventral surface, the first is at the commencement of the rayed dorsal fin, the second at its termination, the third below the anterior part of the adipose dorsal, the fourth below the posterior part of the adipose dorsal and the last in front of the base of the caudal fin. The distal portions of the anterior rays of the dorsal fin are dark and form a broad patch. The oth~r~. fins are somewhat dusky. The colour variations consist in the suppression or intensification of some of these markings, but the general colour plan remains more or less similar. For this reason we have attached no significance to colour variations in recog nising species established on this character alone. Distribution.-Batasio tengana was originally described froln the Brahnlaputra river. We have examined several specimens from below the Darjeeling Himalayas, Assam, Tenasserim, Mergui and Perak. It is also found in Siam (Klong Thalerng, near Ronpibun, Peninsular Siam), from where it was described as Mystus havmolleri by H. M. Smith. In the Siamese examples the eyes are considerably smaller and the adi pose 'dorsal relatively longer. As judged from the figure the barbels, especially the maxillary pair, appear to be somewhat longer. In view of these differences it may perhaps be desirable to regard M. havmolleri as a variety of B. tengana. ~ Measurements in millimetres. (0 ~ d ...... e .....0 ~ ~ ~ 1') ...... Chenderoh I'll Bengal. Assam. I'll bil=~ Lake, d =~p.. • ;; G;) ~ Perak . rn =~ d~~ ~ ~ ~ ,----.-----___--A- __. ------. -A---_"-'\ ,---' ~ Standard length 38·5 40-0 43·5 46·0 48·0 49·0 54·5 54·5 56·0 60·0 41·5 57'5 64·5 68·5 63·0 74·0 53·5 61·0 0 Length of head 10·5 11·0 11·0 12,5 11·5 13·0 15·0 14-5 13·5 15·0 _10·0 15·5 16·5 17·5 16-5 20'5 14·0 17-0 ~>- Height of head at occiput .. 6'5 6·5 7·0 9·0 7-0 9·0 8·5 9·0 10·0 9-5 6·5 9·5 11·0 11-0 11·0 15·0 10·0 9'5 ~ Width of head 7·0 7·0 7·0 8-0 7-0 9-5 9-5 9·5 9·5 10·0 6-5 9·8 12·0 11·5 11·5 14·5 10·0 10·0 ~ Lengt.h of snout 3·5 4-0 4·0 4'5 4·0 5-0 5·5 5·5 5·0 6·0 4·0 5·5 6-0 6-0 5-5 8-5 6-0 7·0 P Diameter of eye 4·0 3·5 3-5 4-0 3·5 4·5 4-5 4-5 4-5 4·5 4·0 5·0 5·0 5'5 6·0 7·0 £)·0 5·0 t"'4 ~ ~ Interorbital width 3·0 3·0 3·0 3·0 3·0 3·5 4·0 3'5 4·0 4·0 2·5 3'5 4·0 4·5 5·0 5·0 4·0 4:·0 Depth of body 9·0 9·0 10'5 11·5 10'5 11·5 12·0 13·0 14·5 15·0 9·5 14·5 14'5 18'5 16·0 19·5 12·5 16·5 C':/.) Length of caudal peduncle 5·0 6·5 8·0 8·0 8·0 6·5 8·0 7·0 11·0 10-5 6·0 9·0 10·0 10·0 7·0 9·0 5·5 7·5 ~. ~ -c~ ~. ~ Least hfight of caudal peduncle 4'5 5·0 5·0 5·7 5·5 5·5 6-5 6·0 7·0 7·0 4·0 6·0 7·5 8·5 7·8 8·0 6·5 6'5 ~ 10·5 13·0 9·0 11·0 13·0 12·0 ~. Longest ray of dorsal 8·0 9·0 9·5 10·0 10·0 11·0 12·0 11·5 D. 16·0 10·0 11·5 ~ Length of dorsal spine 6'5 7·0 7·0 8·5 7'5 8·0 9-0 9·0 9·0 10·0 5-5 8·0 10·0 9·5 9'5 9'5 7·0 7·0 ~ ~ ~ Length of pectoral 8·5 9·0 10·5 8·5 10·5 9·0 11·5 11·0 12·0 10·0 9-0 10-5 14-5 14·0 11·0 17·0 12·0 11·5 ~ ~ Length of pectoral spine 7'5 9·5 8·0 8·0 8-5 8·0 9·0 8·5 9·5 D. 6·5 8·0 10·5 10'5 10·0 13·0 9·5 8-0 ~ Length of ventral 6·5 10·0 9·0 9·5 6-0 9·0 10'5 9·5 9·5 12·0 ~ 6'5 6·5 8·0 7·5 7·0 8'0 9·0 9-5 ~. ~ Longest ray of anal 8-0 6-0 9·0 8·0 10·0 9·5 8·5 11-0 9·5 12·5 8·5 9·5 13-5 13·5 11·0 D. 10·0 10·5 Length of base of anal 6·0 6·5 6·0 7·0 6'5 8·0 7·0 8·5 7-0 10·5 5·5 8·5 10·0 10·0 9·0 12·0 8·0 6·0 LengUl of base of adipose 8·5 10-0 7-5 10·5 12·5 9·5 13·0 12·0 11-5 14·0 7·0 10·5 14·0 17·5 13'5 22·5 13-5 16-0 ~ dorsa1. (,0 40 Records of tke Indian Museum. [ VOL. XLIII, Batasio travaneoria, sp. nov. Plate II, figs. 7-9. D. 2/7 ; A. 3-4/9-11 ; P. 1/7-9; V 1/5; C. 16-19. Batasio travancoria is an elongated, nledium-~ized fish, in which the dorsal profile is slightly arched while the vent.ral profile is lllore or less horizontal in front of the pelvic fins, after which it is slightly arched. The ventral surface of the head and the anterior part of the body are somewhat flattened. The fish is suboylindrical anteriorly and compressed posteriorly. The head is globular, conical and rounded anteriorly; its length is contained froDl 3·87 to 4·35 times in the standard length. The height of the head is contained from 1·44 to 1·81 times and its "ridth from 1·32 to 1·53 times in its length. The snout is rounded and projects beyond the mouth for a short distance; it is longer than the postor bital part of the head. The eyes are of a moderate e-ize and are dorso lateral in position; they are not visible from the ventral surface. The diameter of the eye is contained from 2·72 to 3·10 times in the length of the head, from 0·93 to 1·28 times in the length of the snout and from 0·50 to 0·81 times in the interorbital width. The nostrils are situated wide apart; the anterior nostrils are tubular and are directed forwards while the posterior nostrils are situated much nearer the eye than the anterior nostrils and are provided with nasal barbels. The llledian groove on the head is long and narrow; it extends from slightly in front of the posterior nostrils to the base of the occipital process or slightly farther and in it are lodged two fontanels separated by a narrow ridge. At the sides of the median groove there is a series of 3 small fontanels on either side. The occipital process is long and sharply pointed pos teriorly ; it is separated from the basal bone of the dorsal fin by a con siderable distance. The mouth is small, inferior, lunate and horizontal; it is bordered by fleshy lips which are pendulous and continuous at the angles of the mouth; the labial groove is widely interrupted. The lips are slightly crenulate but not fimbriate as in the other two species. There are five large oval pores behind the lower lip and two series of six pores each situated obliquely between the angle of the mouth and the gill-cover. There are pores between the nostrils, below the eyes and along the free borders of the gill-covers. The teeth are small and villiform; they are arranged in bands in the jaws and on the palate. There are eight barbels; the nasal barbels are situated at the anterior border of the posterior nostrils and extend to about the middle of the eye; the maxillary barbels are short and do not extend beyond the eyes; the outer mandibular barbels are as long as the nasal barbels while those of the inner pair are much shorter. The bases of the mandi bular barbels are not situated in a straight line; those of the inner pair are in, advance of those of the outer. The gill-openings are extensive and the gill-membranes are notched anteriorly. The depth of the body is contained from 4·86 to 5·48 times in the standard length. The least h~ight of the caudal peduncle is contained from 1·01 to 1·29 times in its length. The portion of the body where 1941.] S. L. HORA & N. C. LAW: Siluroid Fishes of lpilia. 41 the air-bladder comes in contact with the skin is fairly well marked extern~lly, and the cubito-humeral processes can be readily felt through the skIn. The external features of the urinogenital organs are similar to those described for the other species. The urinogenital papilla iR well marked, especially in the males. 6. Text-fig. 3.-Alimentary canal, dentition and air-bladder of Batasio travancoria. sp. nov. . a. Alimentary canal. X ca 21. b. Dentition: X 15. c. Air-bladder. X 21. The rayed dorsal fin is situated almost entirely in advance of the pelvics; its longest ray is considerably shorter than the head. The dorsal spine is comparatively weak and is slightly crenulated along both the borders; it is slightly longer than half the length of the head. The adipose dorsal commences as a slightly raised ridge behind the base of the rayed dorsal, but afrer the termination of the dorsal when laid flat it becomes a long, prominent ridge; the length of its base is considerably greater than the length of the head. The pectoral fin is considerably shorter than the head and is separated from the pelvics by about half of its length. The pectoral spine is moderately developed; it is smooth exrernally but denticulated internally. The pelvic fiIl.8 are horizontal and extend considerably beyond the anal opening to the urinogenital papilla. The anal fin is low and the length of its base is almost equal to the base of the rayed dorsal fin. The caudal fin is D 42 Records of the Indian Museum. [VOL. XLIII, deeply forked with the lobes rounded; the lower lobe is bettep. developed than the upper. The colouration in spirit is uniformly gray with the exception of a narrow dark streak along the lateral line. The gray colour is some .. what deeper on the head and the dorsal surface and lighter on the side. The ventral surface is much lighter. All the fins are more or less dusky. JJistribution.-Batasio travancoria is represented in the collection of the Zoological Survey of India by five specimens, which were collected by Dr. C. C. John from the following localities in Travancore : Locality. No. of specimens. Peruntenaruvi, a tributary of the Pamba R., at Edakadathy •• 1 Kolathupuzha, a tributary of the Kallada R. 2 Chittar R., Palode 1 Kallada R., 4 miles east of Thenmalai •• 1 Type-specimen.-F. 13449/1, Zoological Survey of India. (Indian Museum), Calcutta. M easulements in millimetres. Standard length ·. 56·5 59·0 65·0 74·0 79·0 Length of head 14·5 15·0 15·5 17·0 20'5 Height of head at occiput 8·0 10·0 10·0 11·8 14·0 Width of head 10-0 9·8 11·2 12·8 14·5 Length of snout ·. 5·0 5-7 6·4 6'5 7·0 Diameter of eye ·. 5·2 5·5 5·0 5'5 7·5 Interorbital width •• 3·8 3·0 4·0 4·5 3·7 Depth of body ·. 11·5 11·5 12·0 15·2 14·5 Length of caudal peduncle 7·5 6·6 8·0 10·0 9·5 Least height of caudal peduncle 5·8 6·5 6·5 8·0 8·5 Longest ray of dorsal 11·3 12·0 12·4 14·0 15·0 Length of dorsal spine 8·5 9·0 9·5 10·0 10·5 Length of pectoral •• 12·0 11·5 12·0 13·4 15·2 Length of pectoral spine 10·0 10·0 10·0 11·0 12·0 Length of ventral •. 9-0 10·0 11·0 12·0 12·5 Longest ray of anal 11·0 11.;5 10·4 10·8 11·8 Length of base of anal 8·5 8·0 9·0 11·0 12·5 Length of base of adipose dorsal 21·0 17·8 22·8 24·0 30-5